I often speak to people who don’t understand the nature of depression at all. They are convinced they’ve been depressed — “once after a break-up I cried for three days and listened to Nick Cave a lot, but I just pulled myself together and stopped being depressed”, which kinda suggests you’re just too weak or lazy to un-depress yourself. All it takes is pulling yourself up by the bootstraps, they suggest. Why don’t you stop being depressed? It’s easy!
Except, of course, it isn’t, and they have no clue what they are talking about. Bipolar depression is a chemical imbalance in the brain. (Apparently latest studies suggest it is a sort of inflammation.) You can’t stop being depressed any more than you could stop having cancer. There are ways to improve your mood, but when you’re in the darkest pits, those ways aren’t likely to work. For instance, physical exercise helps, but knowing that doesn’t help much when you can barely get dressed without assistance and taking a shower seems to be the same level of difficulty as climbing Mount Everest without oxygen tanks.